Clinical Trials Phase 1

For many new therapeutic treatments, the first use in a human subject occurs during phase 1 of a clinical trial. Learn about phase 1 trials and the goals and design of this clinical trial phase.

Safety of a Phase 1 Trial

When a clinical trial first begins, the effects of the treatment or device in a living patient are undetermined. For this reason, phase 1 trials are considered riskier than later phases and involve very few volunteers (typically 20 to 80 people).

In some phase 1 trials, volunteers are healthy individuals who are paid for their time and travel expenses. In other cases, volunteers are patients who aren’t responding well to existing treatments and are willing to take a potential risk on an experimental drug or procedure.

Primary Purposes of a Phase 1 Trial

In a phase 1 trial, one of the main objectives is to determine how much of a new drug can be given before negative reactions start to develop. Knowing this dose limit helps researchers decide what doses of the drug to use in later clinical trial phases.

Phase 1 is also designed to monitor the safety of the drug, device or procedure. Volunteers are observed closely and often undergo repeated lab tests to see how the body is responding to the treatment. If a treatment appears to be unsafe in humans, the clinical trial is aborted. However, despite the risks associated with phase 1, most exploratory new drugs pass this phase with satisfactory results and advance to a phase 2 trial.

Researchers may also use the phase 1 trial to determine how best to administer a new drug. For example, they may compare a pill form of the drug to an intravenous injection.

Overall, the primary purposes of phase 1 trials are to ensure the treatment is safe enough to advance to a phase 2 trial and to establish reasonable testing conditions for phase 2.

Resources

Center Watch. (n.d.). Overview of clinical trials. Retrieved December 3, 2010, from http://www.centerwatch.com/clinical-trials/overview.aspx

Clinical Trials. (2007). Understanding clinical trials. Retrieved December 3, 2010, from http://clinicaltrials.gov/ct2/info/understand

National Cancer Institute. (2010). Cancer clinical trials. Retrieved December 3, 2010, from http://www.cancer.gov/cancertopics/factsheet/Information/clinical-trials

National Cancer Institute. (2007). New approaches to cancer drug development: Questions and answers. Retrieved December 3, 2010, from http://www.cancer.gov/newscenter/qa/2007/phasezeronextqa

National Marrow Donor Program. (n.d.). What is a clinical trial? Retrieved December 3, 2010, from http://www.marrow.org/PATIENT/Undrstnd_Disease_Treat/

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